Article
Physics, Multidisciplinary
Shaowen Chen, Minhao He, Ya-Hui Zhang, Valerie Hsieh, Zaiyao Fei, K. Watanabe, T. Taniguchi, David H. Cobden, Xiaodong Xu, Cory R. Dean, Matthew Yankowitz
Summary: Twisted monolayer-bilayer graphene (tMBG) systems exhibit various correlated metallic and insulating states, as well as topological magnetic states. The phase diagram of tMBG can be switched under different perpendicular electric fields, providing a tunable platform for investigating correlated and topological states.
Article
Materials Science, Multidisciplinary
Brian T. Schaefer, Katja C. Nowack
Summary: Valleys in hexagonal two-dimensional systems with broken inversion symmetry possess intrinsic orbital magnetic moment, but require uniaxial strain and in-plane electric field to introduce nonzero net magnetization. Studies suggest that Bernal-stacked bilayer graphene can achieve significant orbital magnetization under certain conditions, and the magnetoelectric susceptibility can switch sign with changes in in-plane electric field and carrier density.
Article
Multidisciplinary Sciences
Ido Schwartz, Yuya Shimazaki, Clemens Kuhlenkamp, Kenji Watanabe, Takashi Taniguchi, Martin Kroner, Atac Imamoglu
Summary: In this study, Moire superlattices in transition metal dichalcogenide bilayers were used as a platform to explore strong correlations with optical spectroscopy. By investigating a MoSe2 homobilayer structure, the researchers demonstrated electric field-controlled manipulation of the ground-state hole-layer pseudospin, as well as the observation of an electrically tunable two-dimensional Feshbach resonance in exciton-hole scattering. These findings may pave the way for the realization of degenerate Bose-Fermi mixtures with tunable interactions.
Article
Chemistry, Multidisciplinary
Medha Dandu, Garima Gupta, Pushkar Dasika, Kenji Watanabe, Takashi Taniguchi, Kausik Majumdar
Summary: This study demonstrates the effects of Moire superlattice on excitons and trions in a twisted bilayer of MoS2. The results show that the optical and electrical properties of the system can be controlled by the moire superlattice, providing additional degrees of freedom such as twist angle.
Article
Optics
Xingqiao Chen, Qi Meng, Wei Xu, Jianfa Zhang, Zhihong Zhu, Shiqiao Qin
Summary: This paper presents a perfect absorption metasurface constructed with graphene and lithium niobate, demonstrating electrically tunable absorption and promising applications.
Article
Engineering, Electrical & Electronic
Ze-Tao Huang, Hao-Yi Jiang, Zi-Ye Wang, Ye-Ming Qing, Bing-Xiang Li
Summary: We propose a thermally-electrically tunable perfect absorber based on amorphous silicon (a-Si) and graphene, which can achieve narrow bandwidth perfect absorption due to guided-mode resonance. The resonance wavelength can be thermally tuned with high efficiency and linear controllability through Joule heating, thanks to the linear relationship between refractive index of a-Si and temperature. Additionally, by adjusting the gate voltage, the chemical potential of graphene can be electrically modified, enabling a rapid switching of perfect absorption and perfect reflection. The proposed absorber features a simple structure, perfect absorption, and efficient thermal-electric tunability, showing great potential in applications such as modulators, optical switches, and selective filters.
IEEE PHOTONICS TECHNOLOGY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Eva A. A. Pogna, Andrea Tomadin, Osman Balci, Giancarlo Soavi, Ioannis Paradisanos, Michele Guizzardi, Paolo Pedrinazzi, Sandro Mignuzzi, Klaas-Jan Tielrooij, Marco Polini, Andrea C. Ferrari, Giulio Cerullo
Summary: The ability to tune the optical response of single layer graphene via electrostatic gating is crucial for optoelectronic applications.
Article
Nanoscience & Nanotechnology
Elias Portoles, Shuichi Iwakiri, Giulia Zheng, Peter Rickhaus, Takashi Taniguchi, Kenji Watanabe, Thomas Ihn, Klaus Ensslin, Folkert K. de Vries
Summary: In this study, a superconducting quantum interference device (SQUID) has been constructed in magic-angle twisted bilayer graphene (MATBG) with control over the superconducting phase difference through a magnetic field. The observation of magneto-oscillations of the critical current demonstrates the long-range coherence of superconducting charge carriers in the material, with potential applications in various devices.
NATURE NANOTECHNOLOGY
(2022)
Article
Physics, Multidisciplinary
Xiao-Wei Zhang, Yafei Ren, Chong Wang, Ting Cao, Di Xiao
Summary: We have developed a first-principles quantum scheme to calculate the phonon magnetic moment in solids. By studying gated bilayer graphene, a material with strong covalent bonds, we have found significant and tunable phonon magnetic moments contrary to classical theory predictions. Our results emphasize the importance of quantum mechanical treatment and propose covalent materials with small-gap as promising platforms for investigating tunable phonon magnetic moment.
PHYSICAL REVIEW LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Hyunwoo Park, Sodam Jeong, Changwon Seo, Hyeongi Park, Donghak Oh, Jae-Eon Shim, Jaeyeong Lee, Taewoo Ha, Hyeon-Don Kim, Soojeong Baek, Bumki Min, Teun-Teun Kim
Summary: In this study, the researchers demonstrate that the phase retardation of a THz wave can be electrically controlled by integrating patterned mono- and bilayer graphene onto an isotropic metasurface. By modulating the conductivity of graphene, the refractive index for one of the polarization states can be controlled, allowing for the manipulation of electromagnetic wave polarization states. This work opens up opportunities for the development of compact THz polarization devices and polarization-sensitive THz technology.
Article
Chemistry, Multidisciplinary
Dongwon Shin, Hyeonbeom Kim, Sung Ju Hong, Sehwan Song, Yeongju Choi, Youngkuk Kim, Sungkyun Park, Dongseok Suh, Woo Seok Choi
Summary: Graphene and LaCoO3 hybrid heterostructure exhibits electrically tunable spin-exchange splitting, providing an opportunity for spin polarization control in spintronic devices.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Physical
Dong Ding, Kangcheng Sun, Xiaohan Chen, Chao Wang, Dongfeng Diao
Summary: In this study, a graphene nanocrystalline film device with electrically tunable magnetoresistance behavior at room temperature is designed, and a nonlinear S-shaped I-V curve is observed. By adjusting the grain size of the graphene nanocrystalline, a high linear magnetoresistance is achieved with a large switching ability. The electrically tunable linear magnetoresistance at room temperature in this device has intriguing prospects for low-powerconsumption sensitive logic and magnetic random-access memory devices.
Article
Multidisciplinary Sciences
Andreij C. Gadelha, Douglas A. A. Ohlberg, Cassiano Rabelo, Eliel G. S. Neto, Thiago L. Vasconcelos, Joao L. Campos, Jessica S. Lemos, Vinicius Ornelas, Daniel Miranda, Rafael Nadas, Fabiano C. Santana, Kenji Watanabe, Takashi Taniguchi, Benoit van Troeye, Michael Lamparski, Vincent Meunier, Viet-Hung Nguyen, Dawid Paszko, Jean-Christophe Charlier, Leonardo C. Campos, Luiz G. Cancado, Gilberto Medeiros-Ribeiro, Ado Jorio
Summary: The twisted bilayer graphene undergoes self-organized lattice reconstruction, resulting in the formation of a superlattice that modulates vibrational and electronic structures, leading to phenomena such as strong correlations and superconductivity. Although experimental techniques and theoretical models face challenges in observing and describing these effects, nano-Raman spectroscopy can localize some vibrational modes and provide insights into the effects of electron-phonon coupling on the material properties.
Article
Materials Science, Multidisciplinary
Xiu-Cai Jiang, Yi-Yuan Zhao, Yu-Zhong Zhang
Summary: The article presents a way to tune the tiny gap in twisted bilayer graphene into a large gap. Through comprehensive understanding of the physical origin of gap opening, the study reveals that effective interlayer hopping and charge imbalance are key factors in creating a gap. Based on tight-binding calculations, the researchers suggest using periodic transverse inhomogeneous pressure to tune the interlayer hoppings and create a gap of over 100 meV. First-principles calculations further confirm the feasibility of this approach.
Article
Nanoscience & Nanotechnology
Damiano Marian, David Soriano, Emmanuele Cannavo, Enrique G. Marin, Gianluca Fiori
Summary: The recent discovery of two-dimensional (2D) magnetic materials has opened new frontiers for the design of nanoscale spintronic devices. Among these materials, bilayer CrI3 has attracted attention for its antiferromagnetic interlayer coupling and electrically-mediated magnetic state control. In this study, we propose a lateral spin-valve transistor based on bilayer CrI3, which can fully control spin transport using an external electric field. The proposed device, working in the ballistic regime, can filter and select the spin current with high efficiency (>99%) and an ON/OFF ratio of up to 10^2, utilizing a double split-gate architecture. These findings, obtained through a multiscale approach, suggest the potential of bilayer CrI3 or related 2D magnet materials as a promising platform for electrically tunable and scalable spintronic devices.
NPJ 2D MATERIALS AND APPLICATIONS
(2023)
Article
Physics, Condensed Matter
A. T. Costa, N. M. R. Peres
Summary: The close proximity between graphene sheets and monolayers of 2D superconductors can lead to hybridization between their collective excitations. Heterostructures formed by combinations of graphene sheets and 2D superconductor monolayers show distinct features on the near-field reflection coefficient that can be observed in scanning near-field microscopy experiments, providing a promising platform for probing the many-body physics of superconductors.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Physics, Multidisciplinary
Ke Huang, Hailong Fu, Danielle Reifsnyder Hickey, Nasim Alem, Xi Lin, Kenji Watanabe, Takashi Taniguchi, Jun Zhu
Summary: In this study, we investigate the control over valley isospin degrees of freedom in bilayer graphene using a perpendicular electric field. We observe a new even-denominator fractional quantum Hall state at filling factor v = 5/2 and the appearance of predicted daughter states and anti-Pfaffian states. These findings pave the way for manipulating valley isospin in bilayer graphene to engineer exotic topological orders and quantum information processes.
Article
Physics, Multidisciplinary
J. P. Santos Pires, S. M. Joao, Aires Ferreira, B. Amorim, J. M. Viana Parente Lopes
Summary: In this study, we present the first theoretical investigation on the transport properties of Weyl semimetals with point defects. We demonstrate that dilute lattice vacancies can induce modifications to the low-energy spectrum, resulting in novel transport effects.
PHYSICAL REVIEW LETTERS
(2022)
Editorial Material
Education, Scientific Disciplines
T. V. C. Antao, N. M. R. Peres
EUROPEAN JOURNAL OF PHYSICS
(2023)
Article
Physics, Condensed Matter
M. F. C. Martins Quintela, N. M. R. Peres
Summary: This paper investigates the behavior of Wannier excitons in hexagonal boron nitride quantum dots, examining the influence of quantum dot dimensions on the excitonic states.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Chemistry, Multidisciplinary
Yingdong Guan, Leixin Miao, Jingyang He, Jinliang Ning, Yangyang Chen, Weiwei Xie, Jianwei Sun, Venkatraman Gopalan, Jun Zhu, Xiaoping Wang, Nasim Alem, Qiang Zhang, Zhiqiang Mao
Summary: Researchers have discovered a new non-centrosymmetric van der Waals semiconductor, Cr0.32Ga0.68Te2.33, which exhibits intrinsic ferromagnetism and could potentially be a candidate for bulk ferrovalley materials.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
A. T. Costa, Mikhail I. Vasilevskiy, J. Fernandez-Rossier, Nuno M. R. Peres
Summary: This article investigates the challenges of forming hybrid plasmon-magnon polaritons in heterostructures and demonstrates the possibility of polaritons formed by graphene plasmons and magnons in two-dimensional ferromagnetic insulators.
Article
Materials Science, Multidisciplinary
Santiago Gimenez de Castro, Aires Ferreira, D. A. Bahamon
Summary: In recent years, Chebyshev polynomial expansions have been applied to study the spectral and transport properties of materials. However, the application of the Chebyshev approach to quantum transport properties of noninteracting mesoscopic systems with leads has been hindered by the lack of a suitable Chebyshev expansion of Landaeur's formula. Here, a hybrid approach combining Chebyshev expansions with complex absorbing potentials is used to calculate the conductance of two-terminal devices, demonstrating its versatility in studying mesoscopic twisted bilayer graphene devices.
Article
Materials Science, Multidisciplinary
Alessandro Veneri, David T. S. Perkins, Aires Ferreira
Summary: The microscopic origin of purely interfacial spin-orbit torques in ultrathin systems is not yet fully understood. In this study, a linear response theory with a nonperturbative treatment is used to predict dampinglike spin-orbit torques that are strictly absent in perturbative approaches. The results show that current-induced spin polarization with nonzero components along all spatial directions can occur in ultrathin systems, contrary to previous perturbative predictions. The angular dependence and dependence upon the scattering potential strength of the resulting spin-orbit torques are analyzed numerically.
Article
Materials Science, Multidisciplinary
J. P. Santos Pires, S. M. Joao, Aires Ferreira, B. Amorim, J. M. Viana Parente Lopes
Summary: This study analyzes the electronic structure of a cubic T-symmetric Weyl semimetal in the presence of atomic-sized vacancy defects. The results show that isolated vacancies generate nodal bound states with r(-2) asymptotic tails, even in a weakly disordered environment. These states appear as significantly enhanced nodal density of states, which reshape into a nodal peak broadened by intervacancy hybridization into a comb of satellite resonances at finite energies as the concentration of defects increases. This highlights the importance of point defects as a crucial source of elastic scattering that leads to nontrivial modifications in the electronic structure of Weyl semimetals.
Article
Materials Science, Multidisciplinary
Alessandro Veneri, David T. S. Perkins, Csaba G. Peterfalvi, Aires Ferreira
Summary: The generation of spatially homogeneous spin polarization by applying electric current is a fundamental manifestation of symmetry-breaking spin-orbit coupling in solid-state systems. This has a wide range of applications in spintronics. The study shows that twisted van der Waals heterostructures with proximity-induced spin-orbit coupling are excellent candidates for realizing exotic spin-charge transport phenomena due to their highly tunable momentum-space spin textures.
Article
Materials Science, Multidisciplinary
S. M. Joao, J. M. Viana Parente Lopes, Aires Ferreira
Summary: Disorder is a critical factor influencing the behavior of matter, but its true impact is difficult to determine due to quantum interference, entanglement, and proximity to quantum critical points. This study presents a method to obtain the disorder self-energy of low-energy excitations caused by defects and impurities in a crystal. The method allows for mapping out the frequency and wavevector dependence of electronic excitations, providing a powerful framework for studying quantum materials and disordered phases of matter.
JOURNAL OF PHYSICS-MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
M. F. C. Martins Quintela, N. M. R. Peres
Summary: This paper investigates the opening of band gap and excitonic optical response in rhombohedral trilayer graphene under external electric field. The study reveals that the excitonic resonances can be tuned by the electric field, leading to increased localization of excitonic states.
Article
Materials Science, Multidisciplinary
J. C. G. Henriques, Itai Epstein, N. M. R. Peres
Summary: This paper explores the excitonic optical response of biased bilayer graphene using a combination of tight-binding model and the solution of the Bethe-Salpeter equation. The optical selection rules are obtained analytically, followed by the calculation of the absorption spectrum of a biased bilayer encapsulated in hexagonal boron nitride. The theoretical prediction shows excellent agreement with experimental data.
Article
Materials Science, Multidisciplinary
J. C. G. Henriques, B. Amorim, R. M. Ribeiro, N. M. R. Peres
Summary: This paper discusses the optical response resulting from excitonic effect in two types of hBN bilayers: AB and AA'. By converting the four-band Bethe-Salpeter equation into a one-dimensional problem, the numerical burden of calculation is significantly reduced. The study of these bilayers is crucial for understanding twisted bilayers at arbitrary angles.
